Dental wax extruder

ABSTRACT

An instrument for heating and extruding dental impression wax or compound and other thermoplastic materials packed in collapsible containers. Heated and pressurized hydraulic fluid is applied to the containers to heat and extrude their contents.

United States Patent t191 Glasgow [451 Aug. 27, 1974 DENTAL WAX EXTRUDER [54] 1.715.335 5/1929 -Cocks 222/95 2,755,967 7/l956 Anderson etal. 222/389 X [75] lnvemof- Paul J- Glasgow Woodmefe N-Y- 3,549,051 12/1970 encic zzz/|46 R [73] Assignee: Glasgow Products, Inc., Woodmere,v

NJ. Primary Examiner-Stanley H. TOllberg [22] Filed: Nov. 9, 1972 Assistant Examiner-John P. Shannon [21] Appl. No.: 305,180 Attorney, Agent, 0r Firm-Stoll and Stoll [52] U.S. Cl. 222/94, Z22/95, 222/14g2lI7I-2 [57] ABSTRACT [5l] Int. Cl B65d 35/22 An instrument for heatin g and extrudmg dental im- [58] meld 0f Search" Z22/95 94 1.46 HS lfm HE pression wax or compound and other thermoplastic Z22/146 R 386-5 285/243 32/70 materials packed in collapsible containers. Heated and pressurized hydraulic fluid is applied to the containers [56] References Clted to heat and extrude their contents.

UNITED STATES PATENTS l,468,707 9/ 1923 lJohnston 285/243 11 Claims, 2 Drawing Figures Z4 I4 32 .9 /2 22 36 56 Mmmmmmm" a tt 4t *M :T-1f??? "`a \mmmmwmeeaer4wf' E ua-wma i c PATENTLBAUCQYIQM SHEET 2 0F 2 DENTAL wAx EXTRUDER BACKGROUND OF THE INVENTION l. Field of the Invention Specifically, the dental procedure for making molding wax impressions in the mouth. Generally, metered dispensing of heat-softened thermoplastic materials in other procedures and fields.

2. Description of the Prior Art The closest prior art known to applicant consists of the following U.S. patents:

1,751,129 Cocks 2,086,462 Bost 2,982,443 Ellis 3,228,566 Knox 3,439,839 Schumann 3,443,059 Spencer 3,522,654 Schoelz Of these prior art patents, Bost U.S. Pat. No. 2,086,462, Knox U.S. Pat. No. 3,228,566 and Schoelz U.S. Pat. No. 3,522,654 deal with the specific procedure which is the primary concern of this patent application, to wit: the making of dental wax impressions. However, they make use of conventional sticks of dental impression wax, they apply direct heat to soften the wax, and they then apply a mechanical force directly to the softened wax to extrude it. These patents leave unanswered questions concerning methods of cleaning the instruments in which such sticks of dental wax are processed and dispensed, and concerning methods of assuring delivery of sterile or sterilized wax into the mouth.

There appear to be no substantial advantages in the use of the wax dispensing instruments disclosed in Bost, Knox and Schoelz over the time-honored method of softening a stick of dental wax over a flame and then manually applying the softened wax either directly into the mouth or into a molding form which is subsequently placed in the mouth. It does not appear that the Bost, Knox and Schoelz instruments have been widely adopted, if at all, by dental practitioners.

SUMMARY OF THE INVENTION The present invention is of an instrument for heating and extrudin g dental impression wax and other thermoplastic materials, wherein the wax (or other materials) is packed in collapsible containers and is heated and extruded by applying heated and pressurized hydraulic fluid (preferably, in the case of dental wax, water) to the containers. The wax is not touched either to insert it into the instrument, or to process it in the instrument, or extrude it from the instrument. Indeed, even after it is discharged from the instrument it is worked by means of a tamping element on the instrument, so that manual handling or working of the material is entirely avoided.

More specifically, in the present invention the dental impression wax (or other material) is pre-packaged in the form of handy cartridges, that is, in collapsible containers such as conventional toothpaste tubes. These cartridges are inserted into an instrument which utilizes hydraulic fluid as the heating and pressurizing medium. An electric resistance element heats the hydraulic fluid and the heated fluid heats the cartridge. Manual force, exerted through a piston in a cylinder, pressurizes the heated fluid and thereby applies pressure to the cartridge. The heat-softened wax is thereby extruded from the cartridge and the instrument.

When one cartridge is exhausted, it may be removed and replaced by another cartridge. There is no direct handling of the wax per se and there is a minimum of wax residue left in the instrument. The procedure is clean and simple and contamination of the wax is avoided.

BRIEF DESCRIPTION OF THE DRAWING FIG. l is a longitudinal section through a Dental Wax Extruder made in accordance with the principles of this invention, said extruder being shown in the process of being used to extrude dental wax therefrom.

FIG. 2 is a view of said Dental Wax Extruder partly fragmentary and partly in longitudinal section, showing recharging or replenishing the hydraulic extruding system with additional hydraulic fluid.

DESCRIPTION OF PREFERRED EMBODIMENT OF Tl-IE INVENTION Instrument l0 made in accordance with a preferred form of the invention is shown in the form of a pistol or gun, in a configuration and of a size convenient for holding in the hand and manipulating in relation to a locus operandi in the mouth. It includes a housing consisting of a hollow barrel l2, a forward end cap 14, a rear end cap 16 and a handle 18.

Within barrel 12 is hydraulic fluid chamber 20 containing water or other suitable liquid as the hydraulic fluid. An inlet opening 22 is provided in said barrel to introduce the hydraulic fluid and a plug 24 is provided for closing said opening. Adapted to be supported within said hydraulic fluid chamber is a collapsible cartridge 26 which, in the illustrated form of the invention, is a collapsible tube containing dental impression wax. At room temperature, such wax is a solid which would be difficult to extrude and mold. At known elevated temperatures the wax softens and flows. Preferably the barrel is made of transparent plastics (such as the polycarbonates which are sold by General Electric Company under the trademark LEXAN and by Mobay Chemical Co. under the trademark MERLON) so that the collapsible container may be observed without opening the barrel.

It will be observed that forward cap 14 is detachably secured to barrel l2 by means of a screw-threaded connection 30. or equivalent quick-locking and unlocking means. An O-ring 32 provides a liquid-tight seal between the forward cap and the barrel. Similarly, a screw-threaded connection 34 and O-ring 36 provide a liquid-tight lock between the barrel and rear cap 16.

A tapered discharge nozzle 40 is provided at the forward end of cap 14. Orifice 42 which extends through said nozzle is, at least in part, threaded to receive externally threaded neck 44 of collapsible tube 26. It is by this means, as an illustration, that the collapsible tube may be securely, but removably, supported in hydraulic fluid chamber 20. An O-ring 46 provides a liquid-tight seal between the collapsible tube and end cap 14.

Discharge nozzle 40 is longitudinally split at its forward end and externally threaded to receive a knurled nut 48. The discharge nozzle is thereby enabled to function as a chuck to hold a tubular tip 50 fitted into orifice 42. It is through nozzle 40, and more particularly tubular tip 50 extending into orifice 42, that the wax contents of collapsible tube 26 may be extruded, as will shortly appear. It will also be noted that a bead 52 is secured to the outlet end of tip 50. This bead serves as a tamping element to tamp the extruded wax into the dental molding form.

Supported in cap 16 and extending into hydraulic fluid chamber 20 is an electric resistance heater 54 whose function is to heat the hydraulic fluid in that chamber. A heat-sensitive control 56 (thermostat) is also supported in cap 16 and it too extends into the hydraulic fluid chamber. It is connected to resistance heater 54 to maintain the hydraulic fluid at a given, constant temperature.

The means for pressurizing the hydraulic fluid in chamber 20 will now be described. Mounted in handle 18 is a hydraulic cylinder 60 and mounted in said cylinder is an O-ring encircled piston 62. A plunger 64 (piston rod) is connected at one end to said piston, and it is connected at its opposite end to a link 66. The link is connected to trigger 68 by which the instrument is manually actuated. Pivotal connections 70 and 72 join the link to plunger 64 and trigger 68, respectively, and pivotal connection 74 mounts the trigger to the handle. Pivoted link 66 enables plunger 64 to move in a generally linear path coaxially with cylinder 60. lt is supported for such linear movement by means of bushing 78 mounted in said cylinder. A bracket 76 is secured to plunger 64 adjacent pivotal connection 70, and it functions as a retaining cup or abutment to support one end of a compression spring 80. The opposite end of the compression spring bears against bushing 78. The function of the compression spring is to retract the piston and to return the trigger to its original position. The trigger is thereby cocked and the piston is poised for hydraulic action.

A hydraulic line 82 provides communication between cylinder 60 and chamber 20. A check valve 84 in said hydraulic line allows a flow of hydraulic fluid from the cylinder into the chamber, but blocks a return flow in the opposite direction. A second check valve 86 is connected to cylinder 60, and it functions to admit hydraulic fluid into said cylinder, while preventing an outward flow from said cylinder. Check valve 86 is also connected to a hydraulic fluid reservoir 88 which is formed within handle 18. Hydraulic fluid may be introduced into said reservoir through opening 90. A plug 92 closes the opening.

In the operation of this device, the trigger is pressed against the handle, thereby causing the piston to move toward the closed end 60a of the cylinder. Pressure is thereby applied to the hydraulic fluid in the cylinder and through hydraulic line 82 and hydraulic fluid chamber 20, to the collapsible container 26. This causes the softened wax in the collapsible container to extrude through nozzle 40 and tip 50. To the extent of the extrusion hydraulic fluid will be forced out of cylinder 60 and out of hydraulic line 82 and into hydraulic fluid chamber 20. The volume of fluid entering said chamber will balance the volume of wax extruded from the collapsible container.

When the trigger is released, spring 80 will cause it to retract to cocked position. This will also retract the piston and produce a negative or suction force in the cylinder. As a result, hydraulic fluid will be drawn out of the reservoir through check valve 86 to replace the hydraulic fluid which was forced out of said cylinder. An air vent 94 at the upper end of the reservoir enables air to enter the reservoir to replace the hydraulic fluid which was transferred from said reservoir to said cylinder.

The foregoing describes a preferred form of the invention, and it is understood that variations and refinements may be incorporated therein within the broad scope of the appended claims. For example, the invention is not limited to the precise form of collapsible container, discharge nozzle and nozzle tip shown in the drawing. All that is required is a suitable type of collapsible container, and convenient means for removably supporting it in the hydraulic fluid chamber in communication with the nozzle and its tip. For sanitary reasons the tip should be quickly detachable and replaceable, and either adapted to be sterilized by conventional dental means or disposable. Nor is the precise hydraulic system critical to the present invention. What is required is a convenient means for applying pressure to the hydraulic fluid and thereby to apply pressure to the collapsible container to extrude its contents.

l claim:

l. An instrument for softening and extruding dental impression wax or compound and other thermoplastic materials which are normally in relatively solid, nonflowable state at room temperature, said instrument comprising:

a. a housing having a hydraulic fluid chamber and a discharge nozzle connected with said housing and communicating with said chamber,

able at room temperature,

c. heating means for heating the hydraulic fluid and thereby applying heat to the collapsible container to heat and soften the thermoplastic material contained therein to fluid state, and

d. pressurizing means for applying pressure to said heated hydraulic fluid and thereby compressing the collapsible container to extrude its heated and softened thermoplastic material through the discharge nozzle.

2. An instrument in accordance with claim l, wherein: y

said collapsible container is removably and replaceably supported within the hydraulic fluid chamber.

3. An instrument in accordance with claim 1,

wherein:

said discharge nozzle is removably and replaceably connected to said housing.

4. An instrument in accordance with claim l,

wherein:

a. the housing is formed with an orifice at one end thereof which provides communication between said hydraulic fluid chamber and said discharge nozzle,

b. said orifice being internally threaded, and

c. said collapsible container having an externally threaded neck which is engageable with said threaded orifice to provide communication between said collapsible container and said discharge nozzle.

5. An instrument in accordance with claim l,

wherein:

a. the housing is formed with an orifice at one end thereof which provides communication between said hydraulic fluid chamber and said discharge nozzle,

b. said housing being also provided with a chuck adjacent said orice,

c. said discharge nozzle being detachably secured by said chuck to said housing in communication with said orifice.

6. An instrument in accordance with claim l,

wherein:

a. the hydraulic fluid pressurizing means comprises a hydraulic cylinder, a piston in said cylinder, and piston actuating means,

b. said hydraulic cylinder being hydraulically connected with the hydraulic fluid chamber in the housing.

7. An instrument in accordance with claim 6,

wherein:

a. a hydraulic line connects the hydraulic cylinder with the hydraulic fluid chamber in the housing, b. a check valve being provided to prevent a return flow of hydraulic fluid from said chamber and through said hydraulic line to said hydraulic cylinder, while allowing a forwardl flow of hydraulic fluid from said hydraulic cylinder, through said hydraulic line, to said chamber.

8. An instrument in accordance with claim 7,

wherein:

a. a hydraulic fluid reservoir is provided for said hydraulic cylinder, and

b. a second check valve is connected between said hydraulic cylinder and said hydraulic fluid reservoir,

c. whereby a flow of hydraulic fluid from the hydraulic cylinder to the hydraulic fluid reservoir is prevented while a flow of fluid in reverse direction from the hydraulic fluid reservoir to the hydraulic cylinder is permitted,

d. the flow of hydraulic fluid from the hydraulic fluid reservoir to the hydraulic cylinder replacing the hydraulic fluid caused to flow from the hydraulic cylinder to the hydraulic fluid chamber inthe housing.

9. An instrument in accordance with claim 8, wherein:

a. a spring-biased plunger is connected to the piston,

and

b. a trigger is connected to the spring-biased plunger,

c. whereby manually actuating the trigger against the spring bias causes the piston to force hydraulic fluid out of the hydraulic cylinder and through the first check valve and hydraulic line into the hydraulic fluid chamber in the housing, and

d. manual release of the trigger results in the spring bias retracting the trigger and piston and causing a flow of hydraulic fluid from the hydraulic fluid reservoir and into the hydraulic cylinder to replace the hydraulic fluid forced into the hydraulic fluid chamber in the housing.

l0. An instrument for softening and extruding dental impression wax or compound and other thermoplastic materials which are normally in relatively solid, nonflowable state at room temperature, said instrument comprising:

a. a housing having a hydraulic fluid chamber and a discharge nozzle connected with said housing and communicating with said chamber,

b. a collapsible container with thermoplastic material contents supported within said chamber in external contact with said hydraulic fluid and connected with said discharge nozzle, said thermoplastic material contents being relatively solid and nonflowable at room temperature,

c. heating means for heating the hydraulic fluid and thereby applying heat to the collapsible container to heat and soften the thermoplastic material contained therein to fluid state,

d. pressurizing means for applying pressure to said heated hydraulic fluid and thereby compressing the collapsible container to extrude its heated and softened theremoplastic material through the discharge nozzle,

e. the housing comprises a tubular barrel, a flrst cap removably secured to the front end of the barrel and a second cap removably secured to the back end of the barrel, said barrel and said first and second caps defining said hydraulic fluid chamber,

g. said first cap being provided with an orifice which communicates with said hydraulic fluid chamber, h. said collapsible tube being supported by said first cap, its discharge nozzle projecting through said orifice, and

. said heating means comprising an electric heating element which is mounted in said second cap and extends into said hydraulic fluid chamber,

j. whereby the hydraulic fluid in said chamber is heated by said electric heating element and the thermoplastic material in said collapsible tube is heated by said hydraulic fluid.

1l. An instrument in accordance with claim 10,

wherein:

the two caps are detachably secured to the tubular barrel by means of screw-threaded connections. 

1. An instrument for softening and extruding dental impression wax or compound and other thermoplastic materials which are normally in relatively solid, nonflowable state at room temperature, said instrument comprising: a. a housing having a hydraulic fluid chamber and a diScharge nozzle connected with said housing and communicating with said chamber, b. a collapsible container with thermoplastic material contents supported within said chamber in external contact with said hydraulic fluid and connected with said discharge nozzle, said thermoplastic material contents being relatively solid and nonflowable at room temperature, c. heating means for heating the hydraulic fluid and thereby applying heat to the collapsible container to heat and soften the thermoplastic material contained therein to fluid state, and d. pressurizing means for applying pressure to said heated hydraulic fluid and thereby compressing the collapsible container to extrude its heated and softened thermoplastic material through the discharge nozzle.
 2. An instrument in accordance with claim 1, wherein: said collapsible container is removably and replaceably supported within the hydraulic fluid chamber.
 3. An instrument in accordance with claim 1, wherein: said discharge nozzle is removably and replaceably connected to said housing.
 4. An instrument in accordance with claim 1, wherein: a. the housing is formed with an orifice at one end thereof which provides communication between said hydraulic fluid chamber and said discharge nozzle, b. said orifice being internally threaded, and c. said collapsible container having an externally threaded neck which is engageable with said threaded orifice to provide communication between said collapsible container and said discharge nozzle.
 5. An instrument in accordance with claim 1, wherein: a. the housing is formed with an orifice at one end thereof which provides communication between said hydraulic fluid chamber and said discharge nozzle, b. said housing being also provided with a chuck adjacent said orifice, c. said discharge nozzle being detachably secured by said chuck to said housing in communication with said orifice.
 6. An instrument in accordance with claim 1, wherein: a. the hydraulic fluid pressurizing means comprises a hydraulic cylinder, a piston in said cylinder, and piston actuating means, b. said hydraulic cylinder being hydraulically connected with the hydraulic fluid chamber in the housing.
 7. An instrument in accordance with claim 6, wherein: a. a hydraulic line connects the hydraulic cylinder with the hydraulic fluid chamber in the housing, b. a check valve being provided to prevent a return flow of hydraulic fluid from said chamber and through said hydraulic line to said hydraulic cylinder, while allowing a forward flow of hydraulic fluid from said hydraulic cylinder, through said hydraulic line, to said chamber.
 8. An instrument in accordance with claim 7, wherein: a. a hydraulic fluid reservoir is provided for said hydraulic cylinder, and b. a second check valve is connected between said hydraulic cylinder and said hydraulic fluid reservoir, c. whereby a flow of hydraulic fluid from the hydraulic cylinder to the hydraulic fluid reservoir is prevented while a flow of fluid in reverse direction from the hydraulic fluid reservoir to the hydraulic cylinder is permitted, d. the flow of hydraulic fluid from the hydraulic fluid reservoir to the hydraulic cylinder replacing the hydraulic fluid caused to flow from the hydraulic cylinder to the hydraulic fluid chamber in the housing.
 9. An instrument in accordance with claim 8, wherein: a. a spring-biased plunger is connected to the piston, and b. a trigger is connected to the spring-biased plunger, c. whereby manually actuating the trigger against the spring bias causes the piston to force hydraulic fluid out of the hydraulic cylinder and through the first check valve and hydraulic line into the hydraulic fluid chamber in the housing, and d. manual release of the trigger results in the spring bias retracting the trigger and piston and causing a flow of hydraulic fluid from the hydraulic fluid reservoir and inTo the hydraulic cylinder to replace the hydraulic fluid forced into the hydraulic fluid chamber in the housing.
 10. An instrument for softening and extruding dental impression wax or compound and other thermoplastic materials which are normally in relatively solid, nonflowable state at room temperature, said instrument comprising: a. a housing having a hydraulic fluid chamber and a discharge nozzle connected with said housing and communicating with said chamber, b. a collapsible container with thermoplastic material contents supported within said chamber in external contact with said hydraulic fluid and connected with said discharge nozzle, said thermoplastic material contents being relatively solid and nonflowable at room temperature, c. heating means for heating the hydraulic fluid and thereby applying heat to the collapsible container to heat and soften the thermoplastic material contained therein to fluid state, d. pressurizing means for applying pressure to said heated hydraulic fluid and thereby compressing the collapsible container to extrude its heated and softened theremoplastic material through the discharge nozzle, e. the housing comprises a tubular barrel, a first cap removably secured to the front end of the barrel and a second cap removably secured to the back end of the barrel, f. said barrel and said first and second caps defining said hydraulic fluid chamber, g. said first cap being provided with an orifice which communicates with said hydraulic fluid chamber, h. said collapsible tube being supported by said first cap, its discharge nozzle projecting through said orifice, and i. said heating means comprising an electric heating element which is mounted in said second cap and extends into said hydraulic fluid chamber, j. whereby the hydraulic fluid in said chamber is heated by said electric heating element and the thermoplastic material in said collapsible tube is heated by said hydraulic fluid.
 11. An instrument in accordance with claim 10, wherein: the two caps are detachably secured to the tubular barrel by means of screw-threaded connections. 